For over a century in the oil and gas industry, most downhole fluid is pumped using conventional pump jack systems. These conventional systems require large transportation costs due to their tremendous weights and sizes. Conventional pump jack systems also encounter difficulties in controlling operating parameters, difficulties in system adjustments, and high installation costs. Adjustments to the conventional pumping units involve separately adjusting stroke length, upstroke speed, and downstroke speed, which requires manpower and a lift crane to pin and unpin the shaft and to adjust counterweight positions. These adjustments are costly and involve safety risks.
Most hydraulic pump jack drive systems directly lift both the rod string and fluid head inside the tubing string, which consumes a large amount of power. These systems are typically used for low production margin wells. Certain hydraulic pump jack systems save energy via N2 counterweight systems, but stroke length and seal life are reduced in these systems for high speed operations.
Desirable improvements to pump jack systems include decreased weight and size, ease of controlling the system remotely, and increased power, system efficiency, and reliability of the drive.